The present invention relates to a resin seal type semiconductor device, and more particularly, to a semiconductor device which supplies electric signals or electric potential from one lead to several pads located away from each other.
As shown in FIGS. 8 and 9, a resin seal type semiconductor device such as DIP (Dual Inline Package) is known.
A rectangular die support 3 is held at the central portion of a pair of parallel frame bodies 2 through hanging pins 4. A plurality of leads 5 which are terminals supplying electric signals are held by the frame bodies 2 through tie bars 6. The leads 5 are positioned along the periphery of the die support 3. A plating portion 7 is formed at the inner end of each lead 5 by gold-plating or silver-plating. A lead frame 1 is composed in this way. As shown in FIG. 9, a semiconductor chip 8 having a plurality of electrode pads 9 along the periphery thereof, is mounted on the central portion of the die support 3.
In this condition, each electrode pad 9 provided along the periphery of the semiconductor chip 8 and the corresponding plating portion 7 formed at the inner end of each lead 5 are connected by a bonding wire. Next, the whole arrangement except for the outer portions of the leads 5 are resin sealed by mold resin 11. Then, the leads 5 and the hanging pins 4 are cut off from the frame bodies 2, and after that, the tie bars 6 are removed and the leads 5 are bent, so that the semiconductor device is composed.
In FIG. 11, the mount paste 12 which glues the semiconductor chip 8 to the die support 3, is conductive on non-conductive adhesive.
Recently, many semiconductor chips having minute wires have been made because of the reduction of the size of the semiconductor chip, so that the wire resistance becomes high and the problem of noise occurs. In particular, it is required to reduce the size of the power supply wires of the semiconductor chip because the power supply wires occupy the greatest part of the area of the semiconductor chip. In this case, the problem of noise is more liable to happen.
When the problem of noise occurs, it is difficult to speed up the operation of the semiconductor device.
In order to solve the situation, it has been proposed that several pads receiving power source (power supply pads) are provided on the semiconductor chip, each power supply pad and lead supplying power source (power supply lead) being electrically connected so that the length of the power supply wires from each power supply pad becomes short. In this way, the wire resistance of the power supply wires of the semiconductor chip may become low.
However, when there is one power supply lead and several power supply pads located far from each other on the semiconductor chip such as when, for example when one power supply pad is located close to the power supply lead, and another power supply pad is located opposite the power supply lead, it is impossible to draw the power supply lead to the another power supply pad because of interference of the other leads, and it is therefore impossible to compose such a semiconductor device.
Incidentally, in addition to the relationship between one power supply lead and several power supply pads, the same situation may occur with respect to the relationship between one lead supplying signals and several electrode pads.